Browse Questions

# Most stable carbonium ion is

$(a)\;P-NO_2-C_6H_4-CH_2^+ \\ (b)\;C_6H_5CH_2^+ \\(c)\;P-Cl-C_6H_4-C_6H_4-CH_2 \\ (d)\;P-CH_3O-C_6H_4-CH_2^+$

All the carbonium ions are primary but (a) and (c) are not much stable because the $NO_2$ and $cl$ groups present intensifies positive charge.
In (d) the charge (positive) of benzyl cation is more dispersed because of $+M$ effect of $-OCH_3$ group.
Hence d is the correct answer.